JP 2014-87874 A describes a robot system including a three-phase inverter electrically connected to a stator winding of a three-phase motor through a power line. In the robot system, a regeneration resistor and a switch connected in series are connected in parallel to an input side of the inverter.
When stopping the robot, the switch is turned on to form a closed circuit including the stator winding, the regeneration resistor, and the switch. A regeneration current generated when the robot is operated to slowdown can be made to emit as thermal energy by the regeneration resistor, such that a dynamic brake can be applied to the motor. Thereby, the robot can be slowdown and stopped.